"When I was on holiday in France a few weeks ago, I bought this beautiful fish from the supermarket," says Marcus Wareing, as he tugs the tiny heart, liver and intestines from a quail. "I got it back to the house and thought, 'What the fuck am I going to do with this?'" Far from his gleaming kitchen at the Berkeley Hotel, in Knightsbridge, London, with its constant, efficient clatter, colour-coded chopping boards and double Michelin-starred menu, he got a taste of what cooking is like for the rest of us. "I was totally out of my comfort zone," he admits.

This morning, however, he is in his element – all puffed up because for the second year running his eponymous restaurant has been named London's best by Harden's Guide. Wareing's star has been steadily rising; for 19 years he was Gordon Ramsay's protege, opening Petrus for him at the Berkeley in 1999. But their relationship ended spectacularly badly last year and, after some legal wrangling, Wareing is now running the restaurant under his own name (confusingly Ramsay retained the Petrus brand and this winter will open a new version around the corner).

Although Wareing says he regrets not a bit of it, he is keen to avoid regurgitating his attack on Ramsay. But, for those who missed it at the time, his outbursts included: "If you were in the cavalry ... [Ramsay would] be that general on the hill yelling: 'Charge you idiots!' You'd all get killed, but he'd slide off to the side." And, "My advice to him is: Put a gun to my head, shoot me, put me in a box and bury me because if you don't, I'll come back and come back. I'll never give up until I get where I want to go."

That's all behind Wareing now and his restaurant looks beautiful – the brandy trolley alone is a sight to behold. I often wonder whether there isn't a hint of theatrical exaggeration in these chef spats. Do they all have a laugh about it over a drink later? "No, it's more serious than that," he says gravely. "If it wasn't for the people involved it would all be done behind closed doors. You see these pathetic spats, and I've had mine now."

Wareing may give as good as he gets in the chef wars, but he comes across as more sincere and likeable than his macho former mentor – there's nothing Neanderthal about Wareing's easy charm and earthy Lancashire twang.

Yet his second cookbook, Nutmeg & Custard, is, at first glance, a little intimidating. It's full of complicated-sounding dishes such as herbed garlic bread with bacon and pine nut crumble. Is it aimed at experienced foodies? "No, kids could cook from this," he says, leafing through the book. "Kids could make this crumpet. And there's popcorn." He admits he got carried away with the popcorn, writing 13 recipes, from a canape-style parmesan and black pepper popcorn with pancetta, to milk chocolate and peanut popcorn clusters – which his three children love to cook with their grandmother.

"The chapters are all related to home and things you find in your cupboard. The idea of this was about flavours of my childhood. So I've included the custard tart that my grandma used to make and that I have cooked for the Queen."

While the nostalgic elements of the book will teach you how to recreate Jaffa Cakes and a Strawberry Mivi ice-cream, it also includes meals that Wareing says are worthy of a one-Michelin-starred brasserie – such as the roasted quail with butternut squash and black olives he demonstrated the prep for earlier. And there are easy brunches such as beef and black bean hash with fried eggs and chips.

He has, in short, tried to please everyone because, as he points out, "I don't know anyone who cooks from a cookbook from front to back. People pick out two or three recipes ... The rest is just all fluff."